Stimulation Of Dendritic Cells Research Articles

Lipidation of pneumococcal proteins enables activation of human antigen-presenting cells and initiation of an adaptive immune response.

Streptococcus pneumoniae remains a significant global threat, with existing vaccines having important limitations such as restricted serotype coverage and high manufacturing costs. Pneumococcal lipoproteins are emerging as promising vaccine candidates due to their surface exposure and conservation across various serotypes. While prior studies have explored their potential in mice, data in a human context and insights into the impact of the lipid moiety remain limited. In the present study, we examined the immunogenicity of two pneumococcal lipoproteins, DacB and MetQ, both in lipidated and non-lipidated versions, by stimulation of primary human immune cells. Immune responses were assessed by the expression of common surface markers for activation and maturation as well as cytokines released into the supernatant. Our findings indicate that in the case of MetQ lipidation was crucial for activation of human antigen-presenting cells such as dendritic cells and macrophages, while non-lipidated DacB demonstrated an intrinsic potential to induce an innate immune response. Nevertheless, immune responses to both proteins were enhanced by lipidation. Interestingly, following stimulation of dendritic cells with DacB, LipDacB and LipMetQ, cytokine levels of IL-6 and IL-23 were significantly increased, which are implicated in triggering potentially important Th17 cell responses. Furthermore, LipDacB and LipMetQ were able to induce proliferation of CD4+ T cells indicating their potential to induce an adaptive immune response. These findings contribute valuable insights into the immunogenic properties of pneumococcal lipoproteins, emphasizing their potential role in vaccine development against pneumococcal infections.

Immunomodulatory properties of Leishmania tarentolae extracellular vesicles containing the Spike protein of SARS-CoV-2

Extracellular vesicles released by the protozoan parasite Leishmania display immunomodulatory properties towards mammalian immune cells. In this study, we have evaluated the potential of extracellular vesicles derived from the non-pathogenic protozoan Leishmania tarentolae towards the development of a vaccine adjuvant. As a proof of concept, we expressed in L. tarentolae a codon-optimized SARS-CoV-2 Spike protein fused to the L. mexicana secreted acid phosphatase signal peptide in the N-terminal and to a 6×-His stretch in the C-terminal. Extracellular vesicles released by the engineered L. tarentolae were isolated by ultracentrifugation and fast protein liquid chromatography and were characterized via nanoparticle tracking analysis and transmission electron microscopy. The recombinant S protein was present in extracellular vesicles released by L. tarentolae, as determined by Western blot analyses and immunoelectron microscopy. Next, we evaluated the immunomodulatory potential of extracellular vesicles containing the S protein towards bone-marrow-derived macrophages and bone-marrow-derived dendritic cells. Our data show that in bone-marrow-derived dendritic cells, extracellular vesicles containing the S protein induced an increased expression of proinflammatory genes compared to plain extracellular vesicles whereas the opposite was observed in bone-marrow-derived macrophages. These findings reveal the immunomodulatory potential of L. tarentolae extracellular vesicles and provide a proof of concept that they can be used as adjuvant in the context of dendritic cell stimulation.

Abstract CT133: A phase 1b multicenter study of anti-TIM3 (S095018/Sym023) in combination with anti-PD1 (Sym021) in patients with advanced/metastatic recurrent biliary tract cancer

Abstract Background: TIM3 is an inhibitory immunoreceptor linked to decreased activity of immune cells in the tumor microenvironment. S095018 is a human anti-TIM3 IgG2 antibody which blocks binding of phosphatidyl serine to TIM3 promoting the stimulation of T-cells, dendritic cells (DCs) and macrophages. Sym021 is a humanized IgG1 antibody that inhibits binding of PD-1 with its ligands PD-L1 and PD-L2. Preclinical data demonstrated that Sym021 combined with S095018 results in enhanced immunostimulatory antitumor activity. Methods: S095018 in combination with Sym021 was tested in patients with advanced/metastatic biliary tract cancer whose disease progressed under treatment with at least one line of systemic therapy and who had not received prior treatment with PD-1/-L1 inhibitors (NCT04641871). The dose/schedule of Sym021 and S095018 was 3mg/kg IV Q2W and 10mg/kg IV Q2W, respectively. Primary endpoints included overall response rate (ORR) using RECIST v1.1 and incidence/severity of adverse events. Key secondary endpoints included PK parameters, disease control rate (DCR), progression free survival (PFS) and overall survival (OS). Results As of 31-Oct-2023, 35 patients with stage IV biliary tract cancer (34 cholangiocarcinoma, 1 gallbladder adenocarcinoma) received S095018 in combination with Sym021. All patients were naïve to prior immune checkpoint inhibitor treatment. Twenty-two patients (62.9%) had received 1 prior antineoplastic systemic treatment for advanced/metastatic disease, 34.3% had received ≥2 prior treatments for advanced/metastatic disease. Overall, 34 patients (97.1%) discontinued treatment, 85.7% due to disease progression. Best overall response was 2 PR (5.7%), 11 SD (31.4%), 18 PD (51.4%) and 4 not evaluable. Median PFS and OS were 1.9 months (90% CI 1.8-3.7) and 13.4 months (90% CI 8.2-27.1) respectively. Disease control rate (CR+PR+SD) with SD≥16 weeks, ≥24 weeks and ≥12 months was 28.6%, 22.9% and 8.6% respectively. Treatment emergent adverse events of any grade occurring in >5% of patients included fatigue, pruritus, alkaline phosphatase increase, amylase increase, IRR (each 8.6%) and hypothyroidism, hyperthyroidism, AST increase, lipase increase and myalgia (each 5.7%). Exploratory biomarker analyses in paired tumor biopsies (N=18) showed an intratumoral increase in CD8 T-cell density, as well as upregulation of gene signatures related to IFNg signaling, antigen presentation, T-cell activation and cytotoxicity upon treatment. Baseline tumor biopsies from the two patients who achieved confirmed PR showed high PD-L1 expression. Conclusions: S095018 in combination with Sym021 exhibited antitumor activity in patients with advanced/metastatic recurrent biliary tract cancer who had not received prior treatment with PD-1/-L1 inhibitors. The combination was well tolerated without new safety signals. Further biomarker analysis is ongoing. Citation Format: Francois Ghiringhelli, Richard Kim, Teresa Macarulla, Irene Moreno, Albiruni Razak, Jordi Rodon, Chih-Yi Liao, Thomas Marron, Judith Raimbourg, Helene Kaplon, Julia Geromini, Najah Harouki, Christelle Rodrigues, Pauline Darcel, Niels Jorgen Skartved, Rikke Hald, Daleen Lopez-Ravnborg, Peng He, Xenophon Ianopoulos, Vasileios Askoxylakis, Nehal J. Lakhani, Sarah Davis, Amit Mahipal. A phase 1b multicenter study of anti-TIM3 (S095018/Sym023) in combination with anti-PD1 (Sym021) in patients with advanced/metastatic recurrent biliary tract cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT133.

Pyroptosis activates conventional type I dendritic cells to mediate the priming of highly functional anticancer T cells

BackgroundInitiation of antitumor immunity is reliant on the stimulation of dendritic cells (DCs) to present tumor antigens to naïve T cells and generate effector T cells that can kill cancer...

Immunomodulatory and Anti-Inflammatory Effects of Vitamin A and Tryptophan on Monocyte-Derived Dendritic Cells Stimulated with Gliadin in Celiac Disease Patients.

Celiac Disease (CeD) is an autoimmune disorder with various symptoms upon gluten exposure. Dendritic cells (DCs) play a crucial role in gliadin-induced inflammation. Vitamin A (retinol; Ret) and its metabolite, retinoic acid (RA), along with tryptophan (Trp) and its metabolite, kynurenic acid (KYNA), are known to influence the immune function of DCs and enhance their tolerogenicity. This research aims to assess the impact of gliadin on DC maturation and the potential of vitamin A and tryptophan to induce immune tolerance in DCs. The monocyte cells obtained from peripheral blood mononuclear cells (PBMCs) of celiac disease patients were differentiated into DCs in the absence or presence of Ret, RA, Trp, KYNA, and then stimulated with peptic and tryptic (PT) digested of gliadin. We used flow cytometry to analyze CD11c, CD14, HLA-DR, CD83, CD86, and CD103 expression. ELISA was carried out to measure TGF-β, IL-10, IL-12, and TNF-α levels. qRT-PCR was used to assess the mRNA expression of retinaldehyde dehydrogenase 2 (RALDH2) and integrin αE (CD103). The mRNA and protein levels of Indoleamine 2, 3-dioxygenase (IDO) was analyzed by qRT-PCR and Western blot assays, respectively. Our findings demonstrate that PT-gliadin enhances the expression of maturation markers, i.e. CD83, CD86 and HLA-DR and promote the secretion of TNF-α and IL-12 in DCs. Interestingly, vitamin A, tryptophan, and their metabolites increase the expression of CD103, while limiting the expression of HLA-DR, CD83, and CD86. They also enhance RALDH2 and IDO expression and promote the secretion of TGF-β and IL-10, while limiting IL-12 and TNF-α secretion. These findings suggest that vitamin A and tryptophan have beneficial effects on PT-gliadin-stimulated DCs, highlighting their potential as therapeutic agents for celiac disease. However, further research is needed to fully understand their underlying mechanisms of action in these cells.

A non-lipid nucleic acid delivery vector with dendritic cell tropism and stimulation

A non-lipid nucleic acid delivery vector with dendritic cell tropism and stimulation

Hybrid LNP Prime Dendritic Cells for Nucleotide Delivery.

The efficient activation of professional antigen-presenting cells-such as dendritic cells (DC)-in tumors and lymph nodes is critical for the design of next-generation cancer vaccines and may be able to provide anti-tumor effects by itself through immune stimulation. The challenge is to stimulate these cells without causing excessive toxicity. It is hypothesized that a multi-pronged combinatorial approach to DC stimulation would allow dose reductions of innate immune receptor-stimulating TLR3 agonists while enhancing drug efficacy. Here, a hybrid lipid nanoparticle (LNP) platform is developed and tested for double-stranded RNA (polyinosinic:polycytidylic acid for TLR3 agonism) and immune modulator (L-CANDI) delivery. This study shows that the ≈120nm hybrid nanoparticles-in-nanoparticles effectively eradicate tumors by themselves and generate long-lasting, durable anti-tumor immunity in mouse models.

Human Dendritic Cell Enrichment and Their Activation of T Cells.

Dendritic cells (DCs) enable the immune system to mount and modulate precisely targeted responses to various threats across the organism by bridging innate and adaptive immunity. Historically, DCs have been classified as conventional (cDC) and plasmacytoid (pDC). More recently, cDCs were acknowledged as a heterogenous population composed of several subsets. Examining the functional diversity of cDCs in healthy homeostasis and pathology requires a robust experimental pipeline, beginning with an efficient enrichment protocol in preparation for cell sorting. Unfortunately, several commercial DC enrichment kits were developed before the discovery of the more recently described DC populations. Here, we detail two approaches to enrich human blood DCs or certain DC subsets and an in vitro protocol to examine DC stimulation of naïve T cells. The methods employed here overcome many hurdles encountered while enriching human DC subsets. Basic Protocol 1 describes a method that will enrich pDC, Axl Siglec6-DC (AS-DC), cDC1, DC2, DC3, monocytes, and human HLA+ cells by crosslinking unwanted cells to erythrocytes. Basic Protocol 2 describes the enrichment of pDC, AS-DC, cDC1, and DC2 but not DC3 via a highly efficient negative magnetic selection that is valuable in circumstances where DC3 is not required. Finally, Basic Protocol 3 describes a conventional protocol to perform a Mixed leucocyte Reaction (MLR) following the isolation of these DC subsets. These methods detail the advantages and pitfalls when isolating a heterogeneous population of cells. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Human peripheral mononuclear phagocyte enrichment Basic Protocol 2: DC enrichment of pDC, cDC1, AS-DC, and DC2 but not DC3 Basic Protocol 3: Basic mixed lymphocyte reaction protocol with sorted human DC subsets.

Differential Recognition of Sporothrix schenckii, Sporothrix brasiliensis, and Sporothrix globosa by Human Monocyte-Derived Macrophages and Dendritic Cells.

Sporotrichosis is a mycosis frequently caused by Sporothrix schenckii, Sporothrix brasiliensis, and Sporothrix globosa. The cell wall is a species-specific fungal structure with a direct role in activating the host's immune response. The current knowledge about anti-Sporothrix immunity comes from studies using S. schenckii or S. brasiliensis and murine cells. Macrophages and dendritic cells detect and eliminate pathogens, and although the function of these cells links innate with adaptive immunity, little is known about their interaction with Sporothrix spp. S. schenckii, S. brasiliensis, and S. globosa conidia or yeast-like cells were co-incubated with human monocyte-derived macrophages or dendritic cells, and the phagocytosis and cytokine stimulation were assessed. These interactions were also performed in the presence of specific blocking agents of immune receptors or fungal cells with altered walls to analyze the contribution of these molecules to the immune cell-fungus interaction. Both types of immune cells phagocytosed S. globosa conidia and yeast-like cells to a greater extent, followed by S. brasiliensis and S. schenckii. Furthermore, when the wall internal components were exposed, the phagocytosis level increased for S. schenckii and S. brasiliensis, in contrast to S. globosa. Thus, the cell wall components have different functions during the interaction with macrophages and dendritic cells. S. globosa stimulated an increased proinflammatory response when compared to the other species. In macrophages, this was a dectin-1-, mannose receptor-, and TLR2-dependent response, but dectin-1- and TLR2-dependent stimulation in dendritic cells. For S. schenckii and S. brasiliensis, cytokine production was dependent on the activation of TLR4, CR3, and DC-SIGN. The results of this study indicate that these species are recognized by immune cells differently and that this may depend on both the structure and cell wall organization of the different morphologies.

Identification of peptides presented through the MHC-II of dendritic cells stimulated with Mycobacterium avium

Mycobacterium avium (M. avium) represents a species of concern, because of its ability to modulate the host’s innate immune response, and therefore influence trajectory of adaptative immunity. Since eradicative response against mycobacteria, and M. tuberculosis/M. avium, relies on peptides actively presented on a Major Histocompatibility complex-II (MHC-II) context, we assessed paradoxical stimulation of Dendritic Cell resulting on immature immunophenotype characterized by membrane minor increase of MHC-II and CD40 despite of high expression of the pro-inflammatory tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) in supernatants. Identification of M. avium leucine rich peptides forming short α-helices shutting down Type 1T helper (Th1), contribute to the understanding of immune evasion of an increasingly prevalent pathogen, and may provide a basis for future immunotherapy to infectious and non-infectious disease.

Impaired function of dendritic cells within the tumor microenvironment.

Dendritic cells (DCs), a class of professional antigen-presenting cells, are considered key factors in the initiation and maintenance of anti-tumor immunity due to their powerful ability to present antigen and stimulate T-cell responses. The important role of DCs in controlling tumor growth and mediating potent anti-tumor immunity has been demonstrated in various cancer models. Accordingly, the infiltration of stimulatory DCs positively correlates with the prognosis and response to immunotherapy in a variety of solid tumors. However, accumulating evidence indicates that DCs exhibit a significantly dysfunctional state, ultimately leading to an impaired anti-tumor immune response due to the effects of the immunosuppressive tumor microenvironment (TME). Currently, numerous preclinical and clinical studies are exploring immunotherapeutic strategies to better control tumors by restoring or enhancing the activity of DCs in tumors, such as the popular DC-based vaccines. In this review, an overview of the role of DCs in controlling tumor progression is provided, followed by a summary of the current advances in understanding the mechanisms by which the TME affects the normal function of DCs, and concluding with a brief discussion of current strategies for DC-based tumor immunotherapy.

Tumor cell lysate with low content of HMGB1 enhances immune response of dendritic cells against lung cancer in mice

To assess the effect of tumor cell lysate (TCL) with low high-mobility group B1 (HMGB1) content for enhancing immune responses of dendritic cells (DCs) against lung cancer. TCLs with low HMGB1 content (LH-TCL) and normal HMGB1 content (NH-TCL) were prepared using Lewis lung cancer (LLC) cells in which HMGB1 was inhibited with 30 nmol/L glycyrrhizic acid (GA) and using LLC cells without GA treatment, respectively. Cultured mouse DCs were exposed to different doses of NH-TCL and LH-TCL, using PBS as the control. Flow cytometry was used to detect the expressions of CD11b, CD11c and CD86 and apoptosis of the stimulated DCs, and IL-12 levels in the cell cultures were detected by ELISA. Mouse spleen cells were co-cultured with the stimulated DCs, and the activation of the spleen cells was assessed by detecting CD69 expression using flow cytometry; TNF-β production in the spleen cells was detected with ELISA. The spleen cells were then co-cultured with LLC cells at the effector: target ratios of 5:1, 10:1 and 20:1 to observe the tumor cell killing. In the animal experiment, C57/BL6 mouse models bearing subcutaneous LLC xenograft received multiple injections with the stimulated DCs, and the tumor growth was observed. The content of HMGB1 in the TCL prepared using GA-treated LLC cells was significantly reduced (P < 0.01). Compared with NH-TCL, LH-TCL showed a stronger ability to reduce apoptosis (P < 0.001) and promote activation and IL- 12 production in the DCs. Compared with those with NH-TCL stimulation, the DCs stimulated with LH-TCL more effectively induced activation of splenic lymphocytes and enhanced their anti-tumor immunity (P < 0.05). In the cell co-cultures, the spleen lymphocytes activated by LH-TCL-stimulated DCs showed significantly enhanced LLC cell killing activity (P < 0.01). In the tumor-bearing mice, injections of LH-TCL-stimulated DCs effectively activated host anti-tumor immunity and inhibited the growth of the tumor xenografts (P < 0.05). Stimulation of the DCs with LH-TCL enhances the anti-tumor immune activity of the DCs and improve the efficacy of DCbased immunotherapy for LLC in mice.

Glucan from Dictyophora rubrovolvata boosts immunity by regulating AKT‐STAT1 pathway to induce dendritic cells maturation and T cells differentiation

AbstractGlucan from fruit body of Dictyophora rubrovolvata (DRP) exerts immunomodulation activity, but the mechanism is still elusive. The immunoregulatory effects of DRP were evaluated using cyclophosphamide (CTX)‐induced immunosuppression in BALB/c mice. Furthermore, bone marrow dendritic cells were used to investigate the activated effect of DRP on immune cells in vitro. This study pointed out that DRP recuperated CTX‐induced immunosuppression of BALB/c mice and activated dendritic cells (DCs) to increase the secretion of cytokines in vitro. RNA‐sequencing showed that DRP upregulated the C‐type lectin receptor (CLR), AKT‐STAT1, and Th17 cell differentiation pathways in DCs. Furthermore, western blot and immunofluorescence confirmed that DRP increased the phosphorylation of AKT and STAT1 and the nuclear translocation of STAT1. Intriguingly, flow cytometry showed that the activation of DCs by DRP was interrupted by Mincle (a CLR) and STAT1 inhibitor. Furthermore, co‐cultured experiments demonstrated that DRP promoted naïve CD4+ T cell differentiation to Th17 cells via the stimulation of DCs. Hence, this study implied that DRP regulated the AKT‐STAT1 signaling pathway via Mincle in DCs to induce CD4+ T cell proliferation and differentiation, thereby ameliorating CTX‐induced immunosuppression.

Abstract 2740: Safe and effective delivery of antibody fragments to the solid tumor microenvironment

Abstract Promising immunotherapeutics, particularly agonists, have shown limited clinical benefit, in part because of dose-limiting toxicities, caused by potent immune activation in systemic compartments, with limited evidence of activity in the tumor microenvironment (TME). The Tumor Specific Immunogene (T-SIGn) platform is designed to generate vectors that can express combinations of transgenes producing immunotherapeutics selectively within the tumor microenvironment. T-SIGn is clinically validated for intravenous delivery, enabling the vectors to reach primary and metastatic sites to replicate and produce their therapeutic transgene payloads specifically in malignant epithelial cells. Transgene (TG) cassettes of T-SIGn vectors can be up to approximately 3.5Kb, allowing the expression of multiple distinct TGs. NG-350A is a clinical stage T-SIGn vector, with an established safety/tolerability profile, that expresses a full-length agonist CD40 antibody, and shows evidence of target engagement and adaptive immune activation in patients with different epithelial solid tumors via prolonged, dose-dependent increases in IL-12p70, IFNγ and IL-17A detected in the circulation of patients about 2 weeks after the initiation of the day 1, 3, 5 dosing regimen. NG-350A is currently being evaluated in phase I clinical studies in combination with Pembrolizumab or Ipilimumab. We have been characterizing numerous smaller fragment antibody formats that enable us to combine their expression with other antibody fragments or immunomodulatory molecules as a T-SIGn vector. An ScFv anti-CD40 fragment antibody design was identified as a potent immunotherapeutic to induce the secretion of IL-12p70 cytokine following stimulation of human monocyte-derived dendritic cells, as well as an enhanced antigen-specific T-cell activation and macrophage conversion to a more pro-inflammatory phenotype. When encoded together with CXCL9 and other immunostimulatory cytokines, the anti-CD40 ScFv has been selected as a potential follow-up to NG-350A that synergistically drives enhanced in vitro T-cell priming, activation and migration. Other checkpoint inhibitor and coactivator antibodies, as both ScFv and camelid VHH formats, have also been encoded individually, in combination with the anti-CD40 antibody fragment or other fragment antibodies to create a set of viral vectors that are being evaluated preclinically as future T-SIGn vector candidates. Data from these studies with initial vectors encoding combinations of functionally active antibody fragments will be presented. Collectively, these clinical and preclinical datasets demonstrate the broad utility of the T-SIGn platform for expressing rationally-designed combinations of antibodies and other natural and synthetic agents within tumors and thus enabling the development of new and potent immunotherapies for patients with solid epithelial cancers. Citation Format: Rachel Bergin, Amandine Pelletier, Manuela Zonca, Alice Muntzer, Meg Snowden, Samuel Hardy, Carla Cerqueira, Tae Hyun-Jang, Rochelle Lear, Masumi Fujinobu, Maria Stella Sasso, Samantha Bucktrout, Brian R. Champion. Safe and effective delivery of antibody fragments to the solid tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2740.

An out-of-equilibrium definition of protein turnover.

Protein turnover (PT) has been formally defined only in equilibrium conditions, which is ill-suited to quantify PT during dynamic processes that occur during embryogenesis or (extra) cellular signaling. In this Hypothesis, we propose a definition of PT in an out-of-equilibrium regime that allows the quantification of PT in virtually any biological context. We propose a simple mathematical and conceptual framework applicable to a broad range of available data, such as RNA sequencing coupled with pulsed-SILAC datasets. We apply our framework to a published dataset and show that stimulation of mouse dendritic cells with LPS leads to a proteome-wide change in PT. This is the first quantification of PT out-of-equilibrium, paving the way for the analysis of biological systems in other contexts.

Enhancement of Immune Response of Bioconjugate Nanovaccine by Loading of CpG through Click Chemistry

CpG is a widely used adjuvant that enhances the cellular immune response by entering antigen-presenting cells and binding with receptors. The traditional physical mixing of the antigen and CpG adjuvant results in a low adjuvant utilization rate. Considering the efficient delivery capacity of nanovaccines, we developed an attractive strategy to covalently load CpG onto the nanovaccine, which realized the co-delivery of both CpG and the antigen. Briefly, the azide-modified CpG was conjugated to a bioconjugate nanovaccine (NP-OPS) against Shigella flexneri through a simple two-step reaction. After characterization of the novel vaccine (NP-OPS-CpG), a series of in vitro and in vivo experiments were performed, including in vivo imaging, lymph node sectioning, and dendritic cell stimulation, and the results showed that more CpG reached the lymph nodes after covalent coupling. Subsequent flow cytometry analysis of lymph nodes from immunized mice showed that the cellular immune response was greatly promoted by the nanovaccine coupled with CpG. Moreover, by analyzing the antibody subtypes of immunized mice, NP-OPS-CpG was found to further promote a Th1-biased immune response. Thus, we developed an attractive method to load CpG on a nanovaccine that is simple, convenient, and is especially suitable for immune enhancement of vaccines against intracellular bacteria.

Selective STING stimulation in dendritic cells primes antitumor T cell responses.

T cells that recognize tumor antigens are crucial for mounting antitumor immune responses. Induction of antitumor T cells in immunogenic tumors depends on STING, the intracellular innate immune receptor for cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) and related cyclic dinucleotides (CDNs). However, the optimal way to leverage STING activation in nonimmunogenic tumors is still unclear. Here, we show that cGAMP delivery by intratumoral injection of virus-like particles (cGAMP-VLP) led to differentiation of circulating tumor-specific T cells, decreased tumor regulatory T cells (Tregs), and antitumoral responses that synergized with PD1 blockade. By contrast, intratumoral injection of the synthetic CDN ADU-S100 led to tumor necrosis and systemic T cell activation but simultaneously depleted immune cells from injected tumors and induced minimal priming of circulating tumor-specific T cells. The antitumor effects of cGAMP-VLP required type 1 conventional dendritic cells (cDC1), whereas ADU-S100 eliminated cDC1 from injected tumors. cGAMP-VLP preferentially targeted STING in dendritic cells at a 1000-fold smaller dose than ADU-S100. Subcutaneous administration of cGAMP-VLP showed synergy when combined with PD1 blockade or a tumor Treg-depleting antibody to elicit systemic tumor-specific T cells and antitumor activity, leading to complete and durable tumor eradication in the case of tumor Treg depletion. These findings show that cell targeting of STING stimulation shapes the antitumor T cell response and identify a therapeutic strategy to enhance T cell-targeted immunotherapy.

Genomic repertoires linked with pathogenic potency of arthritogenic Prevotella copri isolated from the gut of patients with rheumatoid arthritis

ObjectivesPrevotella copri is considered to be a contributing factor in rheumatoid arthritis (RA). However, in some non-Westernised countries, healthy individuals also harbour an abundance of P. copri in the intestine....

Ovalbumin-loaded paramagnetic nano-triangles for enhanced dendritic cell stimulation, T1-MR imaging, and antitumor immunity

Vaccine-based cancer immunotherapy has demonstrated a significant potential for cancer treatment in clinics. Although the efficiencies of vaccines are limited, they can be enhanced by a well-designed antigen delivery system that promotes sufficient antigen presentation of dendritic cells (DCs) for initiating high T cell immunity. Herein, antigen-loaded manganese oxide (Mn3O4) triangular-shaped ultrasmall nanoparticles were prepared to stimulate DC-based immunotherapy under the guidance of T1 magnetic resonance imaging. The FDA-approved triblock copolymer Pluronic® F-68 was used not only to transfer the phase from hydrophobic to hydrophilic but also to enrich antigen loading and improve the biocompatibility of the prepared nanoparticles. Ovalbumin (OVA), a model antigen, was adsorbed on the surface of polymer-coated nanoparticles through electrostatic interaction to form Mn3O4@PF68-OVA nanoparticle-antigen complexes to stimulate DC-based immunization and antigen-specific T cell immunity. The Mn3O4@PF68-OVA nanovaccine (NV) induces negligible toxicity effects against 4T1 and bone marrow-derived dendritic cells (BMDCs) by conventional methods supports the proliferation of intestine organoids, which are an innovative three-dimensional cytotoxicity evaluation system, thereby indicating their potential safety for in vivo cancer therapies. The designed paramagnetic nanovaccine possessed excellent OVA delivery to dendritic-regulated antigen-specific T cells in vitro by stimulating the maturation level of BMDCs. In addition, Mn3O4@PF68-OVA NVs enhance immunity in vivo by increasing the T-cells and M1 macrophages, which suggests improved immunity. Excitingly, vaccination with Mn3O4@PF68-OVA offer complete protection in the prophylactic group and significant tumor inhibition in the therapeutic group against B16-OVA tumor. In addition, the designed nanovaccine demonstrated high T1-MR imaging in the tumor, further justifying enhanced tumor accumulation and capability to real-time monitor the treatment procedure. This study presents a promising nanosystem to design an effective nanovaccine for T1-MR imaging-guided tumor immunotherapy.

Neudesin, A Secretory Protein, Suppresses Cytokine Production in Bone Marrow-Derived Dendritic Cells Stimulated by Lipopolysaccharide

Neudesin, A Secretory Protein, Suppresses Cytokine Production in Bone Marrow-Derived Dendritic Cells Stimulated by Lipopolysaccharide